A proper ebike

Yes — I think I know exactly what your sister is talking about. There are two different German technologies she may be mixing together: ROSE as the bicycle brand, and MAHLE as the motor system. And then there is Bosch’s newer lightweight Performance Line SX mid-drive.

The important distinction

1. MAHLE — probably the “male” motor she mentioned

MAHLE makes very small, light e-bike systems. Its X20 motor is actually located in the rear hub, not the bottom bracket. The motor itself is only about 1.4 kg, and the entire X20 drive system—including battery—is about 3.2 kg. It is designed specifically to make an e-bike feel much more like an ordinary bicycle.

That is the very subtle/elegant approach your sister is probably describing.

2. Bosch Performance Line SX

This is a bottom-bracket/mid-drive motor. It is Bosch’s lightweight system, weighing about 2.05 kg, with the newer software update bringing it to 60 Nm and 600 W peak. It is substantially smaller and lighter than Bosch’s full-power CX motor.

The clever thing about the SX is that it is physically around 20% smaller than the older/full-power Bosch design, with a narrower Q-factor, so the pedals feel more like those of a normal bicycle.

3. ROSE

ROSE is a German bicycle manufacturer, rather than a motor manufacturer. They build very sleek bikes around systems such as Bosch. So your sister may be saying something like “a ROSE with the Bosch SX” rather than ROSE being the motor.

And yes — this technology is available in the U.S.

The bike that immediately jumps out at me for what you are describing is the Orbea Gain.

The Orbea Gain M30 uses the MAHLE X20 rear-hub system, has a 350-Wh integrated battery, carbon frame, and looks remarkably like an ordinary road bicycle. Orbea specifically emphasizes the nearly silent, unobtrusive assistance and natural pedaling.

Orbea currently sells the Gain in the U.S.; the M30 is listed around $6,063, with higher-spec versions going considerably higher.

But there’s an even more interesting Bosch option

The Trek Domane+ SLR is perhaps the American-market bike I’d investigate if your sister’s idea is:

“I want an e-bike where you almost forget that it is an e-bike.”

It uses a TQ mid-drive system, not Bosch, but the result is the same philosophy: very discreet motor integration, relatively low weight, and a normal road-bike appearance. The 2026 Domane+ SLR is listed around 27.9 lb in one current configuration.

And the current e-road-bike field is increasingly moving toward exactly this concept: light motor + relatively small integrated battery + normal bicycle geometry, rather than a 60–70-pound bicycle with a huge motor and battery.

One particularly interesting U.S. choice for you

I’d put these three on your shortlist:

Bike/system

Motor location

Character

Why interesting

Orbea Gain

Rear hub, MAHLE X20

⭐⭐⭐⭐⭐ subtle

Probably closest to your sister’s “elegant German” idea

Trek Domane+ SLR

Mid-drive, TQ

⭐⭐⭐⭐⭐ subtle

Extremely refined, light road e-bike

Bosch SX bike

Bottom bracket

⭐⭐⭐⭐½ natural

Bosch ecosystem + genuinely lightweight motor

There is also the Cannondale Synapse Neo, which is very interesting because it uses a lightweight Bosch system, integrated 400-Wh battery and carbon endurance frame. Cannondale describes the Bosch Performance Line Sprint system as providing up to 55 Nm/600 W while retaining a light, lively ride.

My instinct for you: don’t look at the typical American e-bike first. Your sister is pointing you toward the new European “light e-road/e-gravel” generation, and I think that’s exactly the more interesting category for you—particularly because you already enjoy tennis, pickleball, kayaking and fairly active cycling rather than wanting a heavy commuter e-bike.

If you want, I can next  compare 5–6 actual bikes available around New York/Ohio, including weight, motor, range, price and how easy they are to get serviced, and find the one that most closely resembles the sophisticated Munich bikes your sister is seeing.